Polyuretidiones are well known as curing agents for hydroxyl functional polymers. Polyuretidiones are typically prepared by dimerizing a polyisocyanate to form a uretidione with unreacted isocyanate groups which can then be extended with a polyol to form a polymeric material containing two or more uretidione groups in the polymer chain. Typically the polymer has little if any free isocyanate groups, which is achieved by controlling the stoichiometry of the polyisocyanate, polyol and the use of blocking agent. When combined with hydroxyl-functional polymers the resulting composition can be heated to produce a cured composition. In the curing reaction the uretidione groups disassociate giving isocyanate groups that react with the hydroxyl groups. Although the polyuretidiones are desirable from the perspective that they avoid the handling problems associated with polyisocyanates while still providing for a urethane cure, relatively high temperatures on the order of 150° C. are needed for a complete cure.
It has been found that replacing polyols with polythiols and using a suitable catalyst results in ambient temperature cure compositions. Unfortunately, the pot life of the compositions is very poor.